Most of you have probably heard the sound of chirping crickets on warm summer nights. But did you know that the sound you hear is actually the sound of crickets singing? Some crickets chirp during the day, but most of them start singing after sundown.
So why do crickets chirp at night? In short, crickets chirp at night for three reasons:
- They were sleeping during the day as they are nocturnal
- They are looking for food
- They are calling out to females for mating
The third is the main reason why crickets chirp. A lot of cricket behavior is dictated by their mating patterns. The continuous cricket chirping you hear at night is their diligent attempts to father offspring.
But it oddly goes much deeper than that. For example, crickets have a strange mating ritual that involved chirping. Read on to find out more.
Crickets are nocturnal animals. They sleep during the day and wake up at night to search for food and to mate. The sounds you hear are mating songs sung by male crickets as a courtship call.
Some crickets chirp during the day as well. But those calls are less frequent as they are only mating calls. Most females are asleep during the day as well, so the frequency of the chirps is lower during the day time.
Courtship in the cricket world
Male crickets produce their signature sound by rubbing both of their legs together. The serrations on their legs rub against the sharp edges, producing the shrill sound. This process is called stridulation and is used to attract female crickets for mating.
Female crickets are mute and do not chirp. They fly or walk towards male crickets in response to their mating call.
The female’s behavioral pattern is called phonotaxis. It refers to the movement of an organism to a sound source.
Both male and female crickets hear through ears located in their legs. In outdoor environments, a difference as small as that of 5 decibels can significantly impact the female’s decision to move or not.
The males uplift their wings when they initiate a call. With each sound they produce, the wings rub together to form a pulse. Temperature plays an essential role in dictating the speed of the pulse. The warmer the temperature, the faster the pulse.
Laws of attraction
The males rub their wings and produce loud vibrating sounds to help females locate them. Females use this sound to establish which cricket to approach.
A study by researchers at Bristol, published in the proceeding of the National Academy of Sciences, discovered that these sounds are all about survival. Female crickets are attracted to stronger males. Where other desirability factors can be faked, size cannot.
Larger males produce lower pitch sounds. Smaller males produce sounds at a higher pitch. Females listen intently and gauge the size of the cricket through the pitch. They then respond to the most massive cricket in the district.
Female crickets prefer larger males. They believe that larger males are better at hunting for food and also make for better providers.
A study titled Female Mating Behavior in Field Cricket, published in the Journal of Insect Behavior found that females tend to be pickier when a more extensive range of options is available.
In a female-biased environment, the mating success ratio was 70%, whereas, in a male-biased ratio, the success ratio was half of that witnessed in the former. In the latter, females were more guarded with their advances.
Older male crickets are considered more desirable by females as they supposedly have established territories. Their practical experience in the field also makes them better providers in the eyes of the female.
The study also found that the weight of the female did not make a difference in the male’s desire for mating.
Chirping to establish dominance
Researchers at the Department of Biology at the State University of New York at Fredonia conducted a study on male crickets. The study determined whether or not size, type, and pitch of sound define aggressive intent in males.
A parameter was set to measure aggressive intent in males. The study found that an aggressive song represents Resource Holding Potential and is sung to establish dominance.
High short-term repeatability in both frequency and pitch represents aggression. Males significantly alter their aggression according to the perceived resource value during mating calls. Males, isolated from female companionship for four days or more, are likely to be aggressive.
Surprisingly, male crickets did not show the same levels of aggression in terms of food availability. The fighting intent for both food and mating is the same. However, an assault was only witnessed in the presence of females and as a result of prior isolation.
Males present a selective response to food and females. They only fight for dominance when in fear of losing mating opportunities. When they detect other males around as competition, their chirping turns into a rivalry sound. The song is meant to ward off other males to protect their territory and their females.
Stages of aggression
A study by the Zoology department of The University of Michigan observed the aggressive and sexual behavioral patterns in crickets. Male crickets were observed to identify patterns in aggressive encounters to establish dominance. Most encounters ended with one of the two male counterparts retreating. There are five different levels of aggressive interactions, though.
In the following stages, an encounter refers to any physical contact between the two crickets. It includes, but is not limited to, the joining of antennae or engaging in a headlock.
The first is the mildest interaction between two males. The contact ends without any physical contact. There are no signs of established dominance or retreat.
A meeting that ends without any apparent signs of aggression is considered the second level. One of the two participants retreats, allowing the other to establish dominance.
Aggressive interactions between crickets are of the third level when they result in retreat after mild to moderate one-sided aggression or mild reciprocal aggression.
Moderate to intense aggression displayed by both sides counts as fourth level aggressive contact.
Prolonged combat between the opponents is considered the fifth level. Both participants in this combat are considered strong candidates.
When an encounter takes place, it could end in several ways. One of the opponents may start courting aggressively.
In an alternate scenario, a challenged cricket may even show signs of reciprocal aggression. When threatened, both crickets may engage in physical contact. In this case, they may remain interlocked and stand still for several minutes until one of them gives up.
Mating calls can prove fatal
A male cricket’s mating sound also attracts a type of parasitoid fly called the tachinid fly. Once she finds the male, she lays her eggs on the cricket. When the eggs hatch into larvae, they start feeding on the host body. The cricket dies within a week.
That does not stop them from calling out, though. Males often put their lives at risk in order to find a mate.
Chivalry in males
The male crickets’ primary role is that of a protector as per the findings of the analysis of over 200,000 hours of footage that served to monitor cricket behavior. The males go out of their way to protect their females.
Crickets have a wide range of predators, so the risk of them being prey is high. Despite that, male crickets allow the females to take refuge in the burrows before the males do. Their act of chivalry results in higher death rates among their sex.
Mapping cricket chirps
The difference in songs sung by various crickets is subtle. They vary in pulse number and frequency. Average chirp songs have one to eight pulses with regular intervals in the middle. Courtship songs have faster chirps and varying frequencies, depending on the competition.
Chirp rates also vary by species and temperature. Crickets are cold-blooded insects and become more active with rising temperatures. Because they are nocturnal, they are generally asleep during the day.
Crickets hear vibrations
The sounds these insects produce not only attract mates but predators as well. As a defense mechanism, crickets silence themselves when they hear someone approach.
They are hypersensitive to vibrations and noise. Crickets get a warning nerve impulse whenever they hear the slightest sound or feel a vibration. They immediately quiet down to ward off predators. If you’re wondering what the cricket’s biggest predator is, it’s bats.
Crickets are usually brown or black. Because of their colors, they blend in very well with their surroundings. Their camouflaging colors provide them with protection from a lot of predators. However, bats tend to use echolocation to hunt their prey, so the cricket’s ability to silence itself comes in handy when it’s trying to hide from a bat.
What do crickets eat? Crickets are omnivores, which means that they eat both plants and animals (other insects), depending upon whatever is available to them.
How to sneak up on a cricket? If you want to catch a cricket, we suggest that you follow the chirping sound it makes. It will probably go quiet once it feels your movement. If this happens, stand very still for a while. Eventually, the cricket will decide its safe again and will start chirping. Keep following the sound and repeating the process. Eventually, you’ll find what you’re looking for.
Do crickets chirp faster in the dark? Because crickets are nocturnal, they sleep during the day. Since the temperature has an effect on the speed of a cricket’s chirps, they chirp faster during the day as opposed to the dark of night.